Optionally increase difficulty of Rogue Dungeons for better rewards

I like the skeleton key dungeons but once you’re tackling high SR and Crucible content both the difficulty and rewards in rogue dungeons become relatively lacklustre.

Why not give us a recipe for a new skeleton key once the player has cleared all the rogue dungeons which when used, buffs the enemies, adds more modifiers and increases the rewards at the end?
Another alternative could be to let us use multiple keys at once for the same effect.

Would be an easy, low(ish) effort way of increasing endgame farming option variety.